using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Http;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;

namespace StartupDemo
{
    public class Startup
    {
        // This method gets called by the runtime. Use this method to add services to the container.
        // For more information on how to configure your application, visit https://go.microsoft.com/fwlink/?LinkID=398940
        public void ConfigureServices(IServiceCollection services)
        {
        }

        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
        public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
        {
            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
            }

            app.Use(middleware1);
            app.Use(middleware2);

            app.UseRouting();

            app.UseEndpoints(endpoints =>
            {
                endpoints.MapGet("/", async context =>
                {
                    await context.Response.WriteAsync("Hello World!");
                });
            });
        }

        private Func<RequestDelegate, RequestDelegate> middleware1 = new Func<RequestDelegate, RequestDelegate>(next =>
        {
            Console.WriteLine("middleware1"); 
            return new RequestDelegate(async context =>
            {
                await context.Response.WriteAsync("Func1 start");
                //await context.Response.WriteAsync("Func1 end");
                await next.Invoke(context);
                await context.Response.WriteAsync("Func1 end");
            });
        });

        private RequestDelegate middleware2(RequestDelegate next)
        {
            Console.WriteLine("middleware2"); 
            return new RequestDelegate(async context =>
            {
                await context.Response.WriteAsync("Func2 start");
                //await context.Response.WriteAsync("Func2 end");
                await next.Invoke(context);
                await context.Response.WriteAsync("Func2 end");
            });
        }

        private RequestDelegate middleware3(RequestDelegate next)
        {
            Console.WriteLine("middleware3");
            return new RequestDelegate(async context =>
            {
                await context.Response.WriteAsync("Func3 start");
                //await context.Response.WriteAsync("Func3 end");
                await next.Invoke(context);
                await context.Response.WriteAsync("Func3 end");
            });
        }

        private async Task Func2(HttpContext context)
        {
            await context.Response.WriteAsync("Func2");
        }

    }
}
